1. Field of the Invention
The invention relates to biosensors and, more particularly, to a detection method for sensor membrane of europium titanium oxide as part of a biosensor by using PNIPAAm for wrapping enzymes to increase sensitivity and improve reliability of the biosensor.
2. Description of Related Art
Acid alkaline sensors and biosensors are widely employed for chemical analysis and physical examination in recent years. They cooperate with an enzyme membrane and other enzyme fixing methods for examining changes of the physical body including urine tests, blood glucose tests, etc. Thus, applications are greatly increased.
Ionic field effect transistors are widely used as components of a sensor due to miniature size, quick response time and low cost. Sensors made of ionic field effect transistors are widely used to detect enzymes such as glucose, urea, lactic acid, or uric acid. Enzyme membranes on ionic field effect transistors react with targets to change an acid alkaline value, so that a sensor may sense the changes. Thus, how to secure the enzyme membrane onto the ionic field effect transistors is an issue to be addressed.
Conventionally, enzyme fixing can be done by chemical methods, physical methods, or combinations of chemical and physical methods. However, these conventional methods are disadvantageous due to the following drawbacks. Activities of enzymes are difficult being controlled by chemical methods. Further, enzymes are short lived proteins. Physical methods are done in room temperature and are capable of minimizing the activity loss of enzymes. However, its adhesion is weak, and thus, chemical substances of targets may be lost. Alternatively, seaweed glue is employed to wrap enzymes. However, seaweed glue is not easy to wash after use.
Thus, the need for improvement still exists.